KR20030021937A - Method for link adaptation using Hybrid Automatic Repeat Request in reverse link - Google Patents

Abstract

PURPOSE: A link adaptation method by using a reverse link HARQ(Hybrid Automatic Repeat reQuest) type is provided to effectively control a power and a data rate in a reverse link. CONSTITUTION: A terminal receives an RRC(Reverse Rate Control) bit generated in a base station in the ith frame time, and decides an effective data rate(Reff(i)) according to the RRC bit(S11). The terminal maintains or reduces the effective data rate(Reff(i)) according to its state although the terminal receives a command for increasing the data rate from the base station through the RRC bit(S12,S13). The terminal controls a dedicated data rate of a reverse link and updates the effective data rate(Reff(i)) according to its state(S14-S16). The terminal checks over whether a reception terminal transmits an acknowledgement/negative acknowledgement command about the (i-D)th R-NPDCH(Reverse-New Packet Data CHannel) frame(S18). If the terminal receives the negative acknowledgement command about the (i-D)th R-NPDCH frame, a data rate(DR_RPDCH(i)) of an R-RPDCH(Reverse-Retransmission Packet Data CHannel) transmitted in the ith frame time is updated as a data rate(DR_NPDCH(i-D)) of the R-NPDCH transmitted in the (i-D)th frame time(S19). The terminal compares the updated effective data rate(Reff(i)) with the data rate(DR_NPDCH(i-D))(S20). If the effective data rate(Reff(i)) is greater than or same to the data rate(DR_NPDCH(i-D)), the terminal sets the data rate(DR_NPDCH(i-D)) as the effective data rate(Reff(i))(S22).

Description

Method for link adaptation using Hybrid Automatic Repeat Request in reverse link}

The present invention efficiently supports the hybrid automatic repeat reQuest (abbreviated as HARQ) scheme of the reverse channel, and also combines the HARQ scheme with the dedicated rate control scheme of the reverse channel. The present invention relates to a link adaptation method using a reverse link hybrid automatic retransmission request scheme of 1xEV-DV (1x Evolution-Data & Only).

1x-EV DV is a general term for standardization to support high speed packet data service as well as existing voice service based on the 1x technology of the existing synchronous cdma2000 RTT.

Unlike the existing 1x RTT technology on the air interface, the 1x-EV DV adopts the adaptive modulation and coding (abbreviated as AMC) technique and the HARQ scheme in the forward direction. However, in the reverse direction, it is basically just adding channels to support the AMC technology and the HARQ scheme adopted in this forward direction.

In general, link adaptation techniques include power control and data rate control.

The data rate control is for the receiver to adjust the data rate of the transmitter through a change in the power of the signal being received. To this end, the power level of the signal received at the receiving end should not be a constant level.

However, the purpose of power control is to adjust the level of power received by the receiver so that the modulation and coding techniques currently used in the wireless can be brought to a level that can be operated at a desired level. Therefore, power control and AMC techniques are difficult to use together.

In addition, the power control is to solve the near-far problem occurring in the reverse link, by controlling the transmit power differently for the near terminal and the far terminal from the base station to a certain level of power level of all the terminals received by the base station It has a purpose to match.

In general, however, the reverse link has a near-far problem unlike the forward link, and power control is essential. Therefore, it is difficult to apply AMC techniques such as forward links.

Meanwhile, the HARQ scheme refers to a scheme combining a conventional forward error recovery coding scheme and an automatic repeat request (ARQ) through error detection.

In general, the HARQ method is divided into three types according to the method. The type I HARQ scheme refers to a scheme in which a chase combining form is used at the receiver side by transmitting the same information even when retransmission occurs when an error occurs in the first transmission.

The type II HARQ scheme and the type III HARQ scheme increase the redundancy in each transmission, and the receiver code-combines the first transmission signal or the retransmission signal, resulting in a lower code rate. That is, the type II HARQ scheme and the type III HARQ scheme mean a scheme of obtaining coding gain as compared to chase combining.

In this case, the type II HARQ scheme and the type III HARQ scheme are distinguished from each other by type II when each transmission information is not self-decodable and type when self-decodable. It is divided into III.

As described above, there are differences between the forward channel and the reverse channel, and because of these differences, it is difficult to apply techniques for increasing data throughput in the existing forward link even in the reverse direction.

In general, the HARQ scheme currently considered in the reverse link considers the following.

First, when the turbo code rate is 1/4, the receiving end uses Type I HARQ and applies chase combining.

Secondly, when the turbo code rate is 1/2, the receiver uses incremental redundancy that is increased using HARQ of type II and type III.

The reason for using such a scheme is that the lowest code rate of the turbo code, which is the coding scheme currently used in 1x-RTT, is 1/5.

The first approach is that the use of increased redundancy is not so great when using turbo code at 1/4 code rate, since we have already gained sufficient coding gain.

The second approach is that large coding gains can be obtained by using increased redundancy when the code rate is 1/2.

The HARQ scheme currently considered in the reverse link considers the amount of energy used in the initial transmission and the retransmission to be the same.

As described above, in the case of the reverse link, power control is basically performed, and since the base station uses two receiving antennas for receiving the reverse link, it can be considered as a more stable channel environment than the forward link. have.

Therefore, assuming that the base station can receive only a little more energy from the retransmitted packet compared to the energy obtained by receiving the first packet, it will be able to combine the two packets and perform normal decoding.

In addition, if the same power as the initial transmission is used even when the packet is retransmitted, a problem arises in that it is difficult to apply dedicated rate control for reverse link traffic under consideration.

Accordingly, the present invention has been made in view of the above-mentioned problems of the prior art, and provides a link adaptation method using a reverse link hybrid automatic retransmission request scheme that effectively performs power control and data rate control on a reverse link. It is for.

Another object of the present invention is to provide a link adaptation method using a reverse link hybrid automatic retransmission request scheme that controls power of a retransmitted signal to prevent waste of transmission energy.

According to an aspect of the present invention for achieving the above object, in a mobile communication system having at least one terminal and base stations for performing a wireless connection of the terminal, the base station for adjusting the received signal power level Determining an effective transmission rate that can be transmitted from a terminal according to the generated reverse link transmission rate control information; Comparing the effective transmission rate with the transmission rate of the signal to be retransmitted; And determining a power level of the signal to be retransmitted and determining a transmission rate of a new packet according to the comparison result.

Preferably, when the effective transmission rate is larger than the transmission rate of the signal to be retransmitted, the transmission rate of the newly transmitted signal is set to the effective transmission rate. However, when the effective transmission rate is the same as the transmission rate of the signal to be retransmitted, the transmission rate of the newly transmitted signal is set to the effective transmission rate or half of the effective transmission rate.

Preferably, if the effective transmission rate is greater than or equal to the transmission rate of the signal to be retransmitted, the traffic power versus pilot signal power level of the signal to be retransmitted is greater than the traffic power versus pilot signal power level of the initial transmission signal of the signal to be retransmitted. It becomes small by a certain ratio, and this ratio is any one of 0.5, 0.25, and 0.125.

Preferably, the transmission rate of the signal to be retransmitted is equal to the transmission rate of the initial transmitted signal of the signal to be retransmitted.

Preferably, when the effective transmission rate is smaller than the transmission rate of the signal to be retransmitted, only the signal to be retransmitted is transmitted, and no new transmission signal is transmitted. At this time, the ratio of traffic power to pilot power of the signal to be retransmitted uses all the powers authorized to be used at the time of retransmission, and if the licensed power is defined by the energy reduction factor used in the energy reduction automatic retransmission scheme. If it is smaller than the traffic power, the traffic power defined by the energy reduction factor is used for retransmission.

Advantageously, in using each newly defined channel for the signal to be retransmitted and newly transmitted, according to the chase combining method or the increased redundancy combining method in the base station, the terminal may retransmit the channel and retransmit for the new transmission. Channel multiplexing for the code to transmit to the base station.

In the increased redundancy scheme, each channel comprises: turbo coding an information sequence; Rearranging and interleaving the coded symbols to distinguish redundancy codes that may or may not be included in new transmission and retransmission; Truncating or repeating the interleaved symbols to generate a sequence for the new transmission or retransmission assigned to the assigned transmission rate, and then code multiplexed. In this encoding step, a 1/5 code rate is used.

Further, in the chase combining scheme, each channel further includes turbo coding an information sequence, repeating the coded symbol, puncturing the repeated symbol, and interleaving the punctured symbol. Generated, and then code multiplexed. In this turbo encoding step, 1/4 and 1/2 code rates are used.

Advantageously, each newly transmitted or retransmitted channel comprises turbo encoding an information sequence, rearranging the encoded symbols to distinguish redundancy codes that may or may not be included in new transmission and retransmission, and the rearranged Truncating or repeating a symbol to generate a sequence for the new transmission or retransmission, and generating a serial sequence by time multiplexing the generated sequences; Interleaving the generated serial sequence; And modulating and spreading the interleaved sequence on one channel. In this turbo encoding step, the code rate of the turbo code is 1/5.

Preferably, the transmission rate control information and the ACK / NACK information on the signal to be retransmitted are multiplexed into one channel and transmitted to the corresponding terminal. The transmission rate control information and the ACK / NACK information on the signal to be retransmitted have a phase difference. It is transmitted to the corresponding terminal through I channel and Q channel or Q channel and I channel.

Preferably, the ACK / NACK information of the base station for the signal to be retransmitted is transmitted through an independent channel of the forward link.

Preferably, the transmission rate of the newly transmitted signal is transmitted to the base station through the reverse rate indication channel, and the transmission rate of the signal to be retransmitted is not transmitted to the base station.

Preferably, the base station informs the base station whether the newly transmitted signal and the signal to be retransmitted are multiplexed.

According to another aspect of the present invention for achieving the above object, in a mobile communication system having at least one terminal and base stations for performing a wireless connection of the terminal, the base station for adjusting the received signal power level According to the generated reverse link transmission rate control information, the terminal performing any one of increasing, decreasing, and maintaining an effective transmission rate that can be transmitted; Setting the transmission rate of this transmission frame to the transmission rate of the retransmission frame according to the NACK command of the base station for the frame transmitted before the D frame time; Comparing the effective transmission rate with a transmission rate of a previous frame receiving a NACK; If the effective transmission rate is greater than the transmission rate of the previous frame receiving the NACK, the effective transmission rate is set to the transmission rate of the current frame, and the traffic signal power to pilot signal power ratio of the retransmission frame is constant than the initial transmission frame. Setting the ratio to be small; If the effective transmission rate is equal to the transmission rate of the previous frame receiving the NACK, the transmission rate for the new packet is set to the determined effective transmission rate or half of the effective transmission rate, and the traffic signal power versus pilot signal of the retransmission frame. Setting a power ratio to be smaller than the initial transmission frame by a predetermined ratio; When the effective transmission rate is smaller than the transmission rate of the set retransmission frame, only retransmission data is transmitted, and the transmission power is the maximum power and energy reduction automatic retransmission method that the terminal is allowed to transmit at the time of retransmission by data rate control. Selecting and setting a large value among transmission powers defined by an energy reduction factor used in the method; And performing code multiplexing or time multiplexing on the current frame and the retransmission frame according to the set transmission rate and power ratio.

1 is a diagram illustrating an example of a transport chain configuration of an R-NPDCH for an initially transmitted packet according to the present invention.

2 is a diagram illustrating an example of a transport chain configuration of an R-RPDCH for retransmission packet transmission according to the present invention.

3 is a diagram illustrating another example of a transport chain configuration of an R-NPDCH for an initially transmitted packet according to the present invention.

4 is a diagram illustrating an example of a transport chain configuration of an R-RPDCH for retransmission packet transmission according to the present invention;

5 is a view showing a multiplexed R-NPDCH for initial transmission and R-RPDCH for retransmission according to the present invention.

6A through 6B are flowcharts illustrating a reverse traffic transmission data rate control and an energy reduction reverse automatic retransmission scheme of a base station according to the present invention.

7A to 7B are flowcharts illustrating a reverse traffic transmission data rate control and an energy reduction reverse automatic retransmission scheme of a base station according to another method of the present invention.

8 is a diagram illustrating a transmission chain configuration for applying a TDM scheme according to the present invention.

9 is a view showing an output result of the serial connection block shown in FIG. 8;

FIG. 10 illustrates a structure of a channel multiplexed with a channel for ACK / NACK transmission and a reverse rate control channel according to the present invention.

Hereinafter, a configuration and an operation according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

In the present invention, in applying HARQ to the reverse link, a packet in which a NACK is transmitted from a receiver due to a poor reception state is transmitted at the time of retransmission so that only a small portion of energy is received compared to the received energy of the packet initially transmitted at the time of retransmission. A method for adjusting power is proposed.

In addition, a method of optimizing packet throughput of the reverse link by using the extra energy space obtained by using the energy reduction method in the retransmission for the transmission of a new packet.

Then, we propose a combination of energy reduction automatic retransmission scheme and dedicated data rate control scheme for reverse traffic.

According to the present invention, the number of retransmissions of packet data in the reverse link is fixed to one time. This is because the reverse link can have more stable channel quality under the influence of power control and two receiving antennas used in the base station.

In addition, a method of adjusting the traffic power level of the retransmitted packet is used so that the received energy level at the base station of the retransmitted packet becomes a portion of the received energy level of the initially transmitted packet.

If it is assumed that the received energy level of the initially transmitted packet is 1, the received energy of the retransmitted packet is adjusted to be alpha (0 <alpha ≤ 1). As a result, the base station may combine the received energy of the initially transmitted packet with the received energy of the retransmitted packet and use (1 + α) energy in the decoding process. In this case, the reception energy level of the retransmitted packet can be adjusted to the desired amount because the pilot channel of the reverse link is under reverse power control. Accordingly, the power level of the reverse pilot channel received at the base station is kept constant. And, the power gain value is adjusted so that the transmit power level of the other channels in the reverse direction has a constant ratio with the transmit power level of the pilot channel.

Therefore, the method used in the present invention, when the traffic power to pilot power ratio (T / P) at the initial transmission of the packet to G _first , the traffic power to pilot to use when retransmitting the packet The power ratio G _Re-Tx is adjusted to α · G _first .

With this adjustment, the received energy of the retransmitted packet received by the base station will be 100α% of the received energy of the initially transmitted packet. The α value currently under consideration is one of 0.5, 0.25 and 0.125.

If a value of? Of 0.25 is used, it means that the transmit energy of the retransmitted packet is adjusted so that the received energy of the retransmitted packet received to the base station is 25% of the received energy of the initially transmitted packet.

As described above, when the transmission power level of the energy at the time of retransmission is adjusted, extra transmission energy can be obtained at the time of retransmission. When the extra transmission energy thus obtained is used for the transmission of a new packet, an increase in the data throughput of the reverse link can be obtained.

To this end, the present invention uses a method of multiplexing the retransmission and transmission of a new packet for a packet in which a NACK is transmitted from the receiving end due to poor reception. In this case, the multiplexing techniques considered for multiplexing retransmission packets and new packets are two methods, code division multiplexing (CDM) and time division multiplexing (TDM).

For this purpose, the following channels are defined on the reverse link.

First, a channel for reverse packet transmission is called a reverse packet data channel (R-PDCH). The R-PDCH consists of two sub-channels: Reverse New Packet Data Channel (R-NPDCH) used to transmit new packets and Reverse Retransmission Packet Data Channel (R-RPDCH) for retransmitted packet transmission. .

The two sub-channels are multiplexed using the CDM or TDM scheme.

First, when using the CDM scheme, the R-NPDCH and the R-RPDCH are transmitted on separate physical channels using different Walsh codes.

When using the TDM scheme, one Walsh code is used to multiplex retransmissions and new transmissions on one physical channel in time.

1 to 4 illustrate a transmission chain configuration considering the CDM scheme, and in particular, FIGS. 1 to 2 illustrate a transmission chain configuration of each channel (R-RPDCH and R-NPDCH) in consideration of chase coupling among HARQ schemes. will be.

1 is a diagram illustrating an example of a transport chain configuration of an R-NPDCH for an initially transmitted packet according to the present invention.

2 is a diagram illustrating an example of a transport chain configuration of an R-RPDCH for retransmission packet transmission according to the present invention.

As shown in Figs. 1 and 2, the R-NPDCH or the R-RPDCH includes a frame quality indication bit addition block (101,201), a preliminary and tail bit addition block (102,202), and a turbo encoder (1/4 or Half rate) 103, 203, a first symbol repetition block 104, 205, a symbol puncturing block 105, 206, a channel interleaver 106, 207, and a second symbol repetition block 107, 208. Configure.

First, a 16-bit frame quality indicator bit is added to the packet data transmitted from the upper layer, a tail bit and a reserved bit are added, and turbo encoding is performed.

After this encoding process, a rate matching process with a length of a channel interleaver to be used is performed through a symbol repetition process and a symbol puncturing process.

The second symbol repetition blocks 107 and 208 need to be performed in an appropriate amount of repetition according to the length of the Walsh code to be used in the later modulation block (not shown) and the Walsh cover block (not shown).

Such a structure assumes a type I chase combining in the HARQ method combining process.

1, at the bottom of each block, data rates of R-NPDCH (0, 9.6 kbps, 19.2 kbps, 38.4 kbps, 76.8 kbps, 153.6 kbps, 307.2 when using chase combining or partial chase combining) are shown. kbps, 614.4kbps, 1024kbps) and effective code rate (1/2 or 1/4), symbol repetition factor (2x, 1x, 0), symbol puncturing amount (0, 4096), length of channel interleaver used (1536, 1536, 3072, 6144, 12288, 24576, 24576, 36864).

Similarly, at the bottom of each block in FIG. 2, data rates of R-RPDCH (0, 9.6 kbps, 19.2 kbps, 38.4 kbps, 76.8 kbps, 153.6 kbps) when chase combining or partial chase combining are used. 307.2 kbps, 614.4 kbps, 1024 kbps) and effective code rate (1/2 or 1/4), symbol repetition factor (2x, 1x, 0), puncturing amount of symbol (0, 6144, 12288,12288, 28672) And the length of the channel interleaver (1536, 1536, 3072, 6144, 6144, 12288, 12288, 12288).

The information data rate for the R-RPDCH has the same information data rate as the information data rate of the R-NPDCH used in the initial transmission.

That is, assuming that the data rate used for the transmission of the packet in the initial transmission was 38.4kbps, assuming that an error occurred in the packet and received a NACK from the receiver, the transmission chain corresponding to 38.4kbps of the R-RPDCH during retransmission Use

In addition, in the transmission chain of the R-RPDCH, the code rate of the turbo encoder 203 is equal to the code rate of the R-NPDCH in FIG.

However, since the minimum spreading factor that R-NPDCH can use in the spreading process is 2 while the minimum spreading factor that R-RPDCH can use is limited to 4, the symbol puncturing block (from a certain data rate) The effective code rate after passing 206 is different.

In other words, the transmission data rate up to 76.8 kbps is chased by a 1/4 code turbo code, but for a data rate of more than (153.6 kbps to 1024 kbps) only a portion of the coded codes are retransmitted. Partial combining is performed.

If considering the incremental redundancy transmission process, it is necessary to consider the transmission chain of the R-NPDCH or R-RPDCH as shown in Figs.

3 is a diagram illustrating another example of a transport chain configuration of an R-NPDCH for an initially transmitted packet according to the present invention.

4 is a diagram illustrating an example of a transport chain configuration of an R-RPDCH for retransmission packet transmission according to the present invention.

As shown in Figs. 3 to 4, the R-NPDCH or R-RPDCH for supporting incremental redundancy coupling includes frame quality indication bit addition blocks 301 and 401, spare and tail bit addition blocks 302 and 402, and a turbo encoder. (1/5 rate) 303, 403, symbol rearrangement and interleaving blocks 304, 404, and symbol pruning and repetition blocks 305, 405.

First, a 16-bit frame quality indicator bit is added to the packet data transmitted from the upper layer, a tail bit and a reserved bit are added, and turbo encoding is performed.

After the encoding process, in the symbol rearrangement and interleaving blocks 304 and 404, the redundancy code to be included in the initial transmission frame or the redundancy code to be transmitted in the retransmission frame (redundancy code not included in the previous transmission signal) is distinguished. The order of the symbols is properly adjusted, and the pruning process of the next step can be easily performed by the symbol reordering and interleaving operation. Channel interleaving is also performed in this block 304, 404 to prevent burst errors.

The symbol pruning and repetition blocks 305 and 405 may pre-order the reordered symbols to match the number of encoded symbols allocated to the initial transmission frame or the retransmission frame allocated to each channel (FIG. 3 or 4). Prune or repeat as many symbols.

3 to 4, considering the incremental redundancy combining process, the R-NPDCH or R-RPDCH always uses the turbo encoders 303 and 403 of 1/5 code rate. In addition, the symbol reordering and interleaving blocks 304 and 404 should be designed to serve as a channel interleaver and a re-ordering function for code symbols for an increased redundancy process.

3 to 4 summarize the code rates and interleaving lengths of the turbo encoders 303 and 403 according to the data rates of the R-NPDCH or R-RPDCH.

For reference, a redundancy code represents a code in which an extra symbol sequence is added to a symbol sequence necessary to represent original information in order to detect or correct an error occurring in a data transmission process. In the present invention, this is simply referred to as redundancy, and when retransmission of a packet in which NACK occurs, the case of transmitting another redundancy not transmitted in a previous packet is referred to as increased redundancy.

In FIG. 4, the symbol reordering and interleaving block 404 of the R-RPDCH should use the same interleaving rules as the symbol reordering and interleaving block 304 of the R-NPDCH.

As a result, the order of the rearranged symbols after interleaving is the same in R-NPDCH and R-RPDCH. In this case, the code symbols to be transmitted in the R-RPDH are transmitted in a wrap around manner from the next code symbol of the last code symbol transmitted in the R-NPDCH. In this way, when the base station combines the initial transmission packet and the retransmission packet, the base station can make the effective code rate lowest.

5 is a view showing a multiplexed R-NPDCH for initial transmission and R-RPDCH for retransmission according to the present invention.

Referring to FIG. 5, it is assumed that when an initial transmission packet is transmitted to R-NPDCH at the i-th frame time using R transmission rate, an error occurs in the initial transmission packet and the base station transmits a NACK command to the terminal. .

In this case, for convenience, it is assumed that the terminal performs retransmission for the NACK frame at the i + D th transmission instant. Here, it is assumed that D is a delay time (frame unit) of HARQ.

The terminal knows the transmission data rate R of the initially transmitted R-NDPCH, so that the data rate to be used in the R-RPDCH becomes a predetermined value, that is, R.

As described above, the transmit power of the R-RPDCH is controlled so that the base station can receive only a part of the received energy of the initially transmitted packet. If the T / P ratio of the initially transmitted R-NPDCH is referred to as G _first , the T / P ratio of the R-RPDCH at the time of retransmission is determined as? G _first .

Therefore, when retransmitting, the R-RPDCH will use a transmission chain corresponding to the transmission rate of R in FIG. 2 or 4, and will use α · G _first as the T / P ratio.

5 is a diagram in the case where D is assumed to be 2. FIG. That is, when the base station transmits NACK to packet 1 of R-NPDCH, the UE retransmits packet 1 to NACK through R-RPDCH at frame 3 time. At this time, the transmission rate of the third packet of the R-RPDCH is the same as the transmission rate of the first packet of the R-NPDCH, and the T / P ratio is determined as? G _first . At this time, the data transmission rate of the R-NPDCH is determined according to the following process according to the transmission power that the terminal is allowed to transmit at the time of retransmission.

Now consider the case where the base station controls the traffic transmission data rate of each terminal.

The base station commands the RRC bit through the Forward Common Rate Control Channel (F-CRCCH) to maintain, increase or decrease the reverse traffic transmission data rate of the terminal.

Upon receiving this command, the terminal checks the RRC bit to determine the combined data rate to transmit according to the command of the base station. This combined data rate will determine the transmit power the terminal will use.

In practice, dedicated data rate control performed by the base station is to adjust the total amount of power received by the base station to the terminal. Here, it is assumed that the base station has an excess of α and generates RRC bits to be transmitted to each terminal. That is, the base station assumes that the energy received from the terminal can be up to (1 + α) times and generates the RRC bit.

How to multiplex the R-NPDCH and the R-RPDCH according to the respective data rate control information will be described.

First, assume that the data rate was R at the initial transmission of the R-RPDCH. And assume that the terminal has received a command from the base station to maintain the data rate for the HARQ delay time (frame) of D.

Then, even at the time of retransmission, the terminal should use the transmit power corresponding to the combined data of R. However, when generating the RRC bit from the base station's point of view, since the redundancy of α has already been considered, the terminal uses the data rate of the R-NPDCH as R, and the R-RPDCH uses the data rate of the R and the transmission power of α · G _first . And multiplex the two channels.

As a result, the terminal will additionally use up to 10log (1 + α) dB of energy. If α is considered to be 0.25, the terminal additionally uses up to 0.97 dB of power more than the power allowed from the base station. If α is 0.5, the terminal additionally uses up to 1.7B more than the power allowed from the base station.

However, since the base station has already determined the data rate of R with a margin of about 0.97 dB or 1.7 dB, the degradation in performance due to this can be ignored.

Next, suppose that after the initial packet transmission, the effective combined data rate at the time of retransmission is increased twice as much as the initial transmission data rate after D, which is a delay time of HARQ.

Assume that the initial transmission data rate of R-NPDCH was R. At this time, the R-RPDCH will use the data rate of R and T / P of α · G _first .

And, if the terminal does not meet the maximum power limit (max-power limit) that can transmit or there is a sufficient amount of data to transmit, it is assumed that the transmission data rate of the R-NPDCH increases according to the command of the RRC bit lets do it.

For convenience, let us assume that the transmission data rate of the increased R-NPDCH is 2R. The transmission of the command by the base station to increase the data rate may be considered to be equivalent to doubling the T / P ratio that the terminal can transmit.

In this case, the terminal additionally uses up to 10 log (1 + α / 2) dB of power. If α is 0.25, the terminal additionally uses up to 0.51 dB of power more than the power allowed from the base station. If α is 0.5, the terminal additionally uses up to 0.97 dB of power more than the power allowed from the base station.

However, since the base station already has a redundancy of 0.97 dB (? = 0.25) or 1.7 dB (? = 0.5) when generating the RRC bit, the deterioration in performance due to this can be ignored.

Next, after the transmission of the initial packet, after the delay time D of the HARQ, at the time of retransmission, consider the case where the terminal is commanded to reduce the data rate compared to the initial transmission.

Assume that the initial transmission data rate of R-NDPCH was R. The power that the terminal is allowed to use at the time of retransmission is half of the power used for the initial transmission of the packet. Therefore, in this case, the UE performs retransmission using a T / P value of 0.5 * G _first through the R-RPDCH.

In this case, do not transmit a new packet through the R-NPDCH. If, after the delay time D of the HARQ, the terminal is commanded to reduce the data rate by a quarter compared to the initial transmission at the time of retransmission, the terminal performs only retransmission using a value of 0.25.

The combined algorithm of the above-described HARQ scheme and the dedicated data rate control scheme can be represented through flowcharts such as 6a to 6b as a result.

6a to 6b are flowcharts illustrating a reverse traffic transmission data rate control and a power control process of a base station according to the present invention.

6a to 6b, if there is data to be transmitted, the terminal always starts transmitting data at a transmission rate of 9.6 kbps without permission of the base station. Therefore, R _eff (-1) in 6a to 6b is defined as 9.6 kbps. Then, starting from i = 0 frame time, the terminal receives the dedicated data rate control from the base station.

At the i-th frame time, the terminal receives the reverse rate control (RRC) bit generated by the base station and determines the effective data transmission rate R _eff (i) according to the RRC bit.

If the terminal receives a command to increase the transmission rate from the base station through the RRC bit, the terminal may maintain or decrease the effective data transmission rate according to its own state (S12 or S13).

Similarly, even if the terminal receives a command to maintain the transmission rate from the base station, the terminal may reduce the effective data transmission rate according to its state.

However, if the terminal is commanded to reduce the transmission rate from the base station, the terminal should always reduce the effective data transmission rate. At this time, the base station does not transmit a command to reduce the data transmission rate to the terminal using the effective data transmission rate of 9.6kbps.

As described above, the terminal updates the effective data rate R _eff (i) in accordance with the dedicated data rate control of the reverse link and its state (S14 or S15 or S16). In the present invention, when the terminal increases the data transmission rate is increased by 2 times than R _eff (i-1) (S14), when reducing by 1/2 times than R _eff (i-1) For example (S16).

Next, the terminal checks whether the receiving end transmits ACK / NACK for the (i-D) th R-NPDCH frame (S18).

If the ACK is transmitted from the receiver, the terminal transmits only the R-NPDCH at the i-th frame time. In this case, there is no data transmission in the R-RDPCH. Therefore, the data transmission rate of R-NPDCH is R _eff (i). Accordingly, DR_RPDCH (i), which is the data rate of the R-RPDCH for the i-th frame time, is 0, and DR_NPDCH (i), which is the data rate of the R-NPDCH for the i-th frame time, remains the existing R _eff (i). I use it. In addition, G_RPDCH (i), which is the T / P ratio of the R-NPDCH with respect to the i-th frame time, becomes 0 (S17). The terminal transmits the R-NPDCH and prepares for transmission of the next frame (S25).

If the terminal receives the NACK command for the (iD) th R-NPDCH frame (S18), the DR_RPDCH (i) is updated to the DR_NPDCH (iD) value (S19). The terminal compares the updated effective data rate R _eff (i) with DR_NPDCH (iD), which is the transmission rate of the R-NPDCH transmitted at the (iD) th frame time (S20).

If R _eff (i) is greater than or equal to DR_NPDCH (iD), which is the transmission rate of the R-NPDCH transmitted in the (iD) th frame time, DR_NPDCH, which is the transmission rate of the R-NPDCH to be transmitted in the i th frame time, (i) is set to R _eff (i) (S22). The transmission rate of the R-RPDCH is a value determined in advance at the rate transmitted in the (iD) th R-NPDCH frame.

In this case, the terminal transmits a new packet using the R-NPDCH transmission chain of FIG. 1 or 3 corresponding to the determined transmission rate.

Similarly, for the retransmission packet, the transmission chain of the R-RPDCH of FIG. 2 or 4 corresponding to the data transmission rate in the (i-D) th R-NPDCH frame is used. In this case, as described above, the transmit power of the R-RPDCH is adjusted so that the received energy of the retransmission packet received by the base station is α times the received energy of the initially transmitted packet. To this end, the traffic power to pilot power ratio G_RPDCH (i) of the R-RPDCH uses α · G_NPDCH (i-D) (S22).

If the value of R _eff (i) is half or less than DR_RPDCH (i) which is the transmission rate of the R-NPDCH transmitted in the (iD) th frame time (S21), the R-NPDCH of the R-NPDCH to be transmitted in the i th frame time The transmission rate DR_NPDCH (i) is set to 0 (S23 or S24).

In this case, since it is considered that there is not enough power for transmission of a new packet, all allowable power is used for the retransmission packet. That is, the R-RPDCH transmission chain of FIG. 2 or FIG. 4 corresponding to the data transmission rate in the (iD) th R-NPDCH frame is used, and the transmission power of the R-RPDCH uses all available power at that time. Adjust it to

As an example, explain the above process.

First, it is assumed that the initial transmission rate for the packet is 76.8kbps, and the delay time of HARQ is 3 frame times. In this case, it is assumed that after the initial transmission, the RRC bits of (down, down, up) are received from the base station for three frames. It is assumed that α has a value of 0.25.

If the terminal receives the NACK for the initially transmitted packet, the effective data transmission rate that the terminal can use at the time of retransmission thereof is 38.4 kbps. Since the effective transmission rate is half of the initial transmission rate, no new packet is transmitted at the time of retransmission (DR_NPDCH (i) = 0). The R-RPDCH transmission rate is 76.8kbps, which is the same as the initial transmission rate. do. In addition, the transmission power to be used for retransmission of the packet will use all the allowable power by the effective data rate determined at the time of retransmission. Therefore, the traffic power to pilot power ratio of the R-RPDCH is 0.5 times the traffic to power ratio used in the initial transmission of the packet (G_RPDCH (i) = 0.5G_NPDCH (i-D)).

As another example, it is assumed that after the initial transmission, RRC bits of (up, up, down) are received from the base station for three frames.

If the terminal receives the NACK for the initially transmitted packet, the effective data transmission rate that the terminal can use at the time of retransmission is 153.6 kbps. Since this effective transmission rate is higher than the initial transmission rate, transmission of new packets and transmission of retransmitted packets at time of retransmission are time or code multiplexed.

At this time, the transmission rate of the new packet is 153.6 kbps, which is an effective data transmission rate. Therefore, the transmission rate of the R-NPDCH is 153.6kbps. At this time, the data transmission rate of the R-RPDCH for the retransmission packet will be 76.8kbps, the traffic power to pilot power ratio used will be 0.25 times the traffic to pilot power ratio used in the initial transmission of the packet.

As described above, when using the method of multiplexing the R-NPDCH and the R-RPDCH using the flowcharts of 6a to 6b, if the energy reduction factor α is used as 0.5, some problems may occur in the data rate control. .

As described above, it is assumed that the initial transmission data rate of the packet was R, and the effective data rate determined by the data rate control at the time of retransmission is R. When using the method of 6a to 6b, the terminal additionally uses up to 10log (1 + 0.5) = 1.7dB of power compared to the power that is allowed to transmit. Of course, if the base station generates RRC (Reverse Rate Control) information, considering the method of considering the margin of 1.7dB in advance, the multiplexing method of 6a to 6b does not have any problem. However, this relatively large margin has the disadvantage that the accuracy of reverse data rate control may be reduced. In such a case, instead of using the flowcharts 6a to 6b, the flowcharts of 7a to 7b may be used. 7a to 7b are examples of another multiplexing scheme when using the energy reduction factor α as 0.5.

Comparing 6a to 6b with 7a to 7b, if the initial transmission rate for the packet is R and the effective data rate determined at the time of retransmission is R, 6a to 6b determines the data rate of the R-NPDCH for transmission of a new packet. R _eff (i) which is an effective data rate was set. However, in steps 7a to 7b, in step S33, a method of setting the data rate of the R-NPDCH for the transmission of a new packet to half the rate of R _eff (i), which is an effective data rate, is used.

Note that two methods can be considered if the effective data rate R _eff (i) is 9600 bps. Since 9600bps is the lowest data rate, half of this rate does not exist. Therefore, there may be two methods of using 9600bps at the data transmission rate of R-NPDCH, or two methods of not transmitting data to R-NPDCH. In the former case, it is assumed that an additional allowable power of 1.7 dB may be allowed because the transmission power of 9600bps is not so large.

Second, power control and data rate control in the case of applying the TDM scheme are performed as follows.

In this scheme, when there is a data rate determined according to reverse dedicate rate control, a code symbol and a retransmission for a new packet transmission are formed when a code symbol that can fill the length of the interleaving block for the data rate is formed. It is divided into code symbols for and multiplexed in time and transmitted through a modulation process and a spreading process.

In this method, both retransmission frames and frames for new transmissions are transmitted through one physical channel using one Walsh code.

8 is a diagram illustrating a transmission chain configuration for applying a TDM scheme according to the present invention.

Referring to FIG. 8, CRC and tail bit addition blocks 501 and 506, turbo encoders 502 and 507, sign symbol rearrangement blocks 503 and 508, symbol pruning and repetition blocks 504 and 509, and serial connection block 505 ), A channel interleaver 510, a modulator 511, and a Walsh covering block 512.

8 assumes that the number of retransmissions is limited to one in case of NACK.

In FIG. 8, the upper end serves as a path for transmitting new packet data, and the lower end serves as a path for retransmission.

The CRC and tail bit addition blocks 501 and 506 add a CRC for error checking and tail bits to the information bits to be transmitted to the receiver.

The turbo encoder 502 or 507 encodes the bit string to which the CRC and tail bits are added as a turbo code having a 1/5 code rate.

The code symbol rearrangement blocks 503 and 508 are used to determine the redundancy code included in the initial transmission frame in each path or the redundancy code (redundancy code not included in the previous transmission signal) to be transmitted in the retransmission frame. Adjust the sequence accordingly.

The symbol pruning and repeating blocks 504 and 509 prun or repeat the ordered code symbols by a predetermined number of symbols to match the number of coded symbols allocated for each initial transmission and retransmission.

The serial connection block 505 time-multiplexes each symbol pruned or repeated by each symbol pruning and repetition block 504, 509 to generate a sequence. As shown in Fig. 9, the generated sequence is filled with code symbols for new packet transmission in the upper field of the transmission signal, and code symbols including redundancy codes that have not been transmitted in the previous packet are filled in the lower field.

The channel interleaver 510 interleaves the code symbols of each of an upper field or a lower field among the code symbols filled as described above.

These code symbols are then modulated by modulator 511 and spread using one Walsh code in spreader 512.

The present invention always uses the 1/5 rate turbo encoders 502 and 507 as the base channel encoder in both the path for new packet data transmission and the path for retransmitted packets in order to efficiently use increased redundancy.

The turbo coded code symbols are then passed through code symbol reordering blocks 503 and 508. The role of this block is to rearrange the order of code symbols in order to efficiently support increased redundancy.

Next, pruning or repeating an appropriate amount for the rearranged code symbols to match the number of code symbols allocated to each new packet transmission and retransmission packet.

Through this process, the entire code symbol sequence currently supported by the data rate adjusted by the dedicated rate control is connected to the upper code symbol and the lower code symbol to form a sequence.

Meanwhile, a method of managing ACK and NACK signals in the CDM or TDM scheme is performed as follows.

In order to apply the reverse HARQ scheme, consideration should be given to where to manage the ACK signal and the NACK signal. In other words, consideration should be given to whether the ACK and NACK signals are managed by the base station (BTS) or the control station (BSC).

If the ACK and the NACK are managed by the BSC, the demodulated frames are all raised to the BSC by the BTSs in the active set. The BSC generates an ACK signal if one frame has a good frame and a NACK signal if the frame raised from all BTSs is a bad frame, and all BTSs in the active set are generated. To transmit.

Then all BTSs transmit the same ACK or NACK signal to the terminal. If this method is applied, the terminal can perform soft-combining on the ACK and NACK signals. Therefore, the reliability of the ACK and NACK signals is increased, but the execution delay time of HARQ is increased. It has the disadvantage of being able to.

On the contrary, if the ACK and NACK signals are directly managed by the BTS stage, the aforementioned delay problem between the BSC and the BTS does not occur.

However, since all BTSs in the active set can generate different ACK or NACK signals, the terminal cannot apply soft-combining to these signals.

And, from the standpoint of the terminal, if only one BTS receives an ACK signal among BTSs in the active set, retransmission for the frame is not performed.

The structure of a forward channel for transmitting the ACK and NACK signals is as follows.

Various methods can be considered to form a forward channel for transmitting an ACK signal and a NACK signal to a terminal.

Firstly, a conceivable method is to form one independent physical channel for transmitting ACK and NACK signals. In this case, it is better to accommodate multiple users on one common channel than to use different physical channels for the ACK or NACK signals to be transmitted to the respective terminals.

There is also a need for a channel for dedicated rate control. This channel also transmits RRC (Reverse Rate Control) information to terminals currently transmitting packet data through a reverse channel every frame, and can be multiplexed into one common physical channel together with the ACK / NACK signal.

This multiplexing saves the Walsh code.

FIG. 10 illustrates a structure of a channel multiplexed with a channel for ACK / NACK transmission and a reverse rate control channel according to the present invention. At this time, one Walsh code is used to multiplex corresponding channels.

As shown in FIG. 10, the blocks for the reverse common control channel include repeating blocks 601, 605, 609, 613, signal point mapping blocks 602, 606, 610, 614, channel gains 603, 607, 611, 615, multiplexers 604, 612, and relative offset calculation. The part 608, the decimator 616, and the long code generator 617 are comprised.

I branches are sent with RRC bits for reverse data rate control. The ACK or NACK bits are transmitted to the Q branch. Or vice versa. The channel thus generated will be referred to as a forward common reverse control channel (F-CRCCH).

The I and Q branches define each channel having a phase difference, and generally refer to an orthogonal phase difference.

That is, two channels, a forward common rate control channel (F-CRCCH) subchannel and a forward common acknowledgment channel (F-CACKCH) subchannel, are multiplexed to one F-CRCCH.

One F-CRCCH can accommodate control information for 24 or 48 users.

If accommodating 24 users, one ACK or NACK bit and RRC bits are repeated eight times. In this case, the positions of the repeated bits are placed at even intervals for the entire 20 ms frame time for more diversity gain. That is, when one frame is divided into 16 power control groups (PCGs), control information is transmitted once every 2 PCGs.

If 48 users are accommodated in one F-CRCCH, the control information is repeated four times, and control information is transmitted once every 4 PCGs.

The repetition blocks 601, 605, 609, and 613 input rate control bits or ACK / NACK bits for a plurality of users, and repeat the bits for repetitive transmission for each PCG period for a 20 ms frame time.

The signal point mapping blocks 602, 606, 610, and 614 map 0 to +1, 1 to -1, and 0 if no transmission bit is transmitted. After passing through the signal point mapping blocks 602, 606, 610, and 614, the number of symbols at point A or C is one symbol for every 2 PCG intervals when the number of users is 24, and one symbol for every 4 PCG intervals when the number of users is 48. Outputs

The channel gain units 603, 607, 611, 615 adjust the channel gain of each mapped bit for each user. The channel gain units 606, 607, 611 and 615 assign initial offset values to each user (point B or point D).

The multiplexers 604 and 612 multiplex rate control bits of each user whose gain is adjusted, or multiplex ACK / NACK bits of each user. In this case, the multiplexers 604 and 612 adjust the offset value for each user according to the offset value provided from the relative offset calculator 608.

The long code generator 617 generates a long code according to a long code mask for a reverse control channel, and the decimator 616 detects the long code in units of chips and provides the long code to the relative offset calculator 608. do. Accordingly, the relative offset calculator 608 calculates an offset value for each user and provides the offset value to the multiplexers 604 and 612.

Meanwhile, a reverse channel indicating the data rate of the reverse link is generated as follows.

The R-NPDCH channel is basically a variable data rate channel whose data rate can vary. Accordingly, there is a Reverse Rate Indication Channel (hereinafter referred to as RRI channel) indicating the data rate of the current R-NPDCH. At this time, since the data rate for the R-RPDCH of the present invention is information already known by the base station, no clear indication is required. In the current reverse transmission, one bit of additional information is required to indicate whether transmission of a new packet and transmission of a packet having a NACK are multiplexed with each other.

By designing an efficient HARQ scheme on the reverse link of the current 1x-EV DV, the data throughput of the reverse link is increased.

In addition, it is possible to design an efficient combining method of the dedicated rate control method and the HARQ method for the reverse link. This is made possible by using Chase combining or partial Chase combining, which is a Type II or Type III HARQ scheme or Type I HARQ scheme using an increased redundancy scheme.

In the HARQ scheme of the reverse link, a scheme of reducing the received energy of the retransmitted packet to the received energy of the initially transmitted packet may be used. By using this approach, the remaining extra energy space can be used for transmission for new packets, thereby increasing the packet throughput of the reverse link.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the examples, but should be defined by the claims.

Claims (22)

In a mobile communication system having at least one terminal and base stations performing wireless connection of the terminal, Determining an effective transmission rate that can be transmitted from the terminal according to reverse link transmission rate control information generated by the base station to adjust a received signal power level; Comparing the effective transmission rate with the transmission rate of the signal to be retransmitted; And determining, according to the comparison result, a power level of the signal to be retransmitted and a transmission rate of a new signal to be retransmitted. 2. The link adaptation using the reverse link hybrid automatic retransmission request method according to claim 1, wherein when the effective transmission rate is greater than the transmission rate of the signal to be retransmitted, the transmission rate of the newly transmitted signal is set to the effective transmission rate. Way. 2. The reverse link of claim 1, wherein when the effective transmission rate is the same as the transmission rate of the signal to be retransmitted, the transmission rate of the newly transmitted signal is set to the effective transmission rate or half of the effective transmission rate. Link adaptation method using hybrid automatic retransmission request method. 2. The method of claim 1, wherein if the effective transmission rate is greater than or equal to the transmission rate of the signal to be retransmitted, the traffic power versus pilot signal power level of the signal to be retransmitted is the traffic power versus pilot signal of the initial transmission signal of the signal to be retransmitted. A link adaptation method using a reverse link hybrid automatic retransmission request method, characterized in that the power level is smaller than the power level. 5. The method of claim 4, wherein the predetermined ratio is any one of 0.5, 0.25, and 0.125. The method of claim 1, wherein the transmission rate of the signal to be retransmitted is equal to the transmission rate of the initial transmitted signal of the retransmission signal. The reverse link hybrid automatic retransmission request scheme according to claim 1, wherein when the effective transmission rate is smaller than the transmission rate of the signal to be retransmitted, only the signal to be retransmitted is transmitted and no new transmission signal is transmitted. Link adaptation method used. 8. The method of claim 7, wherein the ratio of traffic power to pilot power of the signal to be retransmitted uses all of the power that is authorized to be used at the time of retransmission, and if the licensed power is an energy reduction factor used in the energy reduction automatic retransmission scheme. If the traffic power is smaller than the traffic power defined by the link adaptation method using a reverse link hybrid automatic retransmission request method characterized in that the traffic power defined by the energy reduction factor is used for retransmission. 2. The method of claim 1, wherein a newly defined channel is used for the retransmitted and newly transmitted signal. 10. The reverse link of claim 9, wherein the terminal code-multiplexes a channel for new transmission and a channel for retransmission according to a chase combining method or an increased redundancy combining method in the base station. Link adaptation method using hybrid automatic retransmission request method. 11. The method of claim 10, wherein in the increased redundancy scheme, each channel is Turbo encoding the information sequence; Rearranging and interleaving the coded symbols to distinguish redundancy codes that may or may not be included in new transmission and retransmission; Using the reverse link hybrid automatic retransmission request scheme, wherein the interleaved symbol is truncated or repeatedly generated to generate a sequence suitable for the transmission rate allocated to the new transmission or retransmission, and then code multiplexed. Link adaptation method. 12. The method of claim 11, wherein the encoding comprises using a 1/5 code rate. The method of claim 10, wherein in the chase coupling method, each channel is Turbo encoding the information sequence, repeating the coded symbol, puncturing the repeated symbol, and interleaving the punctured symbol, and then code multiplexing. A link adaptation method using a reverse link hybrid automatic retransmission request scheme. 14. The method of claim 13, wherein the turbo encoding step uses 1/4 and 1/2 code rates. The method of claim 1, wherein each newly transmitted or retransmitted channel is Turbo encoding an information sequence, rearranging the coded symbols to distinguish redundancy codes that may or may not be included in new transmissions and retransmissions, truncating or repeating the rearranged symbols or repeating the new transmissions or retransmissions Generating a sequence suitable for the assigned transmission rate, Time multiplexing the generated sequences into one serial sequence; Interleaving the generated serial sequence; And modulating and spreading the interleaved sequence on one channel to transmit the information on one channel. 16. The method of claim 15, wherein in the turbo encoding, the code rate of the turbo code is 1/5. The method of claim 1, wherein the transmission rate control information and the ACK / NACK information for the signal to be retransmitted are multiplexed into one channel and transmitted to the corresponding terminal. 18. The reverse link hybrid of claim 17, wherein the transmission rate control information and the ACK / NACK information for the signal to be retransmitted are transmitted to the corresponding terminal through an I channel and a Q channel having a phase difference or a Q channel and an I channel. Link adaptation method using automatic retransmission request method. The method of claim 1, wherein the ACK / NACK information of the base station for the signal to be retransmitted is transmitted through an independent channel of a forward link. 2. The method of claim 1, wherein the transmission rate of the newly transmitted signal is transmitted to the base station through a reverse rate indication channel, and the transmission rate of the signal to be retransmitted is not transmitted to the base station. Link adaptation method 2. The method of claim 1, wherein the base station informs the base station whether the newly transmitted signal and the retransmitted signal are multiplexed. In a mobile communication system having at least one terminal and base stations performing wireless connection of the terminal, Performing, by the base station, any one of increasing, decreasing, and maintaining an effective transmission rate that can be transmitted by the terminal according to reverse link transmission rate control information generated by the base station to adjust a received signal power level; Setting the transmission rate of this transmission frame to the transmission rate of the retransmission frame according to the NACK command of the base station for the frame transmitted before the D frame time; Comparing the effective transmission rate with a transmission rate of a previous frame receiving a NACK; If the effective transmission rate is greater than the transmission rate of the previous frame receiving the NACK, the effective transmission rate is set to the transmission rate of the current frame, and the traffic signal power to pilot signal power ratio of the retransmission frame is constant than the initial transmission frame. Setting the ratio to be small; If the effective transmission rate is equal to the transmission rate of the previous frame receiving the NACK, the transmission rate for the new packet is set to the determined effective transmission rate or half of the effective transmission rate, and the traffic signal power vs. pilot signal of the retransmission frame. Setting a power ratio to be smaller than the initial transmission frame by a predetermined ratio; When the effective transmission rate is smaller than the transmission rate of the set retransmission frame, only retransmission data is transmitted, and the transmission power is the maximum power and energy reduction automatic retransmission method that the terminal is allowed to transmit at the time of retransmission by data rate control. Selecting and setting a large value among transmission powers defined by an energy reduction factor used in the method; And transmitting the current frame and the retransmission frame by code multiplexing or time multiplexing to the base station according to the set transmission rate and power ratio.